Gum based adhesives based on vegetable gums such as xanthan, karaya, tragacanth and acacia were some of the first denture adhesive materials to be developed, and are characterized by modest adhesion to both the dentures and oral mucosa. More recent developments feature denture adhesives commonly containing mixtures of the salts of carboxymethylcellulose and so-called Gantrez polymers; (poly[vinyl methyl ether maleate]) or Polyvinyl alcohol-methyl acrylate copolymer, where the ingredients are then combined with binders (mineral oil, petrolatum and polyethylene oxide), oil based flavoring agents and methyl or poly-paraben as preservatives. Non-toxic naturally derived alternatives have been described as well: U.S. Pat. No. 5,760,102 to Hall, et al. describes a method of preparing a denture adhesive composition containing a chemical substance derived from aloe leaf.
While these products work for their intended use, they are not without disadvantages. Certain gums such as Karaya have been known to cause allergic reactions, and to lower the intraoral pH creating a damaging environment for teeth and increased susceptibility to dental caries. While synthetic (Gantrez type) denture adhesives offer a better performance than the gum based alternatives, they are difficult to remove from the dentures and oral mucosa using only water. They also tend to separate out into constituents of thin and thick viscosities in the tube which can lead to premature hardening of the formulation and product waste. Furthermore, while not intended for ingestion, many denture adhesive users are of advanced age and may swallow a portion. The health effects of ingesting small amounts of denture adhesive over extended periods are not well understood; however, an association between prolonged use of zinc containing denture adhesives and neuropathy has been described; Neerman, et al. “Neuropathy Following Chronic Use of Denture Adhesive in a 40-Year-Old Patient,” Laboratory medicine, vol. 38, (2007): no. 10. Heretofore, denture compositions described containing aloe evidence a low initial pH that can be problematic insofar as a pH below 6.5 is known to degrade hydroxyapatite.
An ideal denture adhesive therefore should be non-toxic (even if swallowed), non-irritating and easy applied and removed; the constituents should not separate in the package over time. Further desirable characteristics would be thin film forming properties, a neutral or slightly basic pH so as not to promote demineralization of tooth enamel and a resistance to fermentation; whereby an acidic environment is created by the oral microflora.
Resistant Starch
So called high amylose or resistant starch is a type of starch that resists digestion in the small intestine. High amylose corn starch (HACS) has a higher ratio of amylose to amylopectin (1:1) than conventional corn starch (1:4). Currently three categories of resistant corn starch are commercially available: Class V (50% amylose), Class VII (70% amylose) and Class IX (90% amylose). These types of resistant corn starches are classified as RS2, meaning that they occur in a naturally granulated form and share this classification with uncooked potato and green banana flour. Unique adhesive and moisture resistant properties of HACS are thought due to the helical non-branching structure of amylose, and described in patents for the packaging industries, specifically for the production of corrugated cardboard:    U.S. Pat. No. 4,787,937 to Leake described the use of an improved corrugating adhesive which is a mixture of raw uncooked tapioca starch and gelatinized hi-amylose starch.    U.S. Pat. No. 5,236,977 to Eden et al. describe the uses of gelantanized hi-amylose starch to improve the tack and green strength of corrugating adhesives.    U.S. Pat. No. 5,393,336 describes the use of hi-amylose starch as the ungelatinized raw starch component in a mixture of cooked starch to produce an adhesive with a high level of water resistance and green bond strength.Glucomannan Hemicelluloses
Soluble partially acetylated glucomannans (GM), a type of hemicellulose, occur as constituents of bulbs, tubers, roots, seeds and the leaves of some non-gramineous monocotyledons such as the genus Aloe and in the tubers of the Amorphophallus kojac plant. They take the form of linear acetylated mucilaginous polysaccharides comprising 1,4-β-linked D-glucosyl and D-mannosyl. The inner gel of the Aloe (Aloe barbadensis (Miller)) plant has a Glc:Man ratio of about 1:2, while the Konjac (Amorphophallus kojac) has a ratio of about 1:1.6. A. Ebringerova et al. “Hemicellulose” Journal of Advanced Polymer Science 186 (2005): 1-67. Acemannan Hydrogel™ a product of Carrington Laboratories, Irving Tex., contains acetylated glucomannan; the first standardized commercially available material derived from raw aloe, and the subject of many studies suggesting various therapeutic effects in wound healing and as part of a bioadhesive drug delivery system; U.S. Patent Application 20070298090 (Chen et al.). The use of complex carbohydrates and specifically acemannan, as a possible denture adhesive has been described. Tello et al. “In vitro evaluation of complex carbohydrate denture adhesive formulations” Quintessence International; vol. 29, issue 9, (1998):
Both types of glucomannan have been recognized for their thin film forming characteristics which is highly desirable for denture adhesives because thick films may displace the denture.    U.S. Pat. No. 5,308,636 to Tye et al. describes enhanced gelatinization of starch with the addition of a glucomannan with improved cling to smooth surfaces such as poultry, fish and vegetables.    U.S. Pat. No. 5,358,559 to Fitt et al describes enhancement of a starch based adhesive with the addition of a hemicellulose.